Power Quality Evaluation in Autonomous Wastewater Treatment Plant

The power quality of a low-capacity domestic wastewater treatment plant with autonomous operation through automatic control of the technological process was analyzed by monitoring/recording the main electrical parameters. Determinations showed that, under concrete operating conditions (average effluent flow 9.8 m
³
/h, 5.9
^°
C water temperature in aerobic and anaerobic bioreactors), the average active power absorbed is 11.103 kW at an average power factor of 0.73- which leads to a specific consumption of 1.125 kWh/m
³
treated water. The evolution of the active power, reactive power, apparent power, power factor, total harmonic distortion of the voltage (THD V), and total harmonic distortion of the current (THD A) parameters show fluctuations determined by the consumers' operating sequences. The frequent starts/stops of inductive consumers by electromagnetic contactors produce transients reflected on the evolution diagrams of the power factor and THD (both in voltage and current).